82 RESEARCHES ON FUNGI 



tw« genera dififer markedly in their basidia. The dimorphism which 

 we find in Coprinus is absent in Bolbitius. Further, on any very 

 small area of the hymenium of Coprinus at maturity all the basidia 

 have full-sized and practically ripe spores on them at one and the 

 same time. On a similar area of the hymenium of Bolbitius adjacent 

 basidia are not in about the same state of development at any one 

 time. Here the basidia develop and discharge their spores in suc- 

 cession and not en masse. 



The upper surface of the pilei of the two species of Bolbitius 

 which I have investigated is covered with a thin gelatinous cuticle 

 which is formed from the swollen outermost walls of the exterior 

 cells, and which can be torn away in strips from mature fruit-bodies 

 (Fig. 37, D and E, p. 77). Such a gelatinous cuticle does not occur 

 in connection with any of the thirty species of Coprinus which I 

 have now examined. The upper surface of the pileus of a Coprinus 

 is made up of (1) a continuous layer of thin-walled palisade cells 

 some of which may be produced into unicellular hairs, or (2) loose 

 spherical or elongated cells which constitute a mealy powder, or 

 (3) masses of adherent cells which make up larger or smaller scales. 

 It would therefore appear that the presence of a continuous 

 gelatinous layer on the pileus of Bolbitius and its absence from 

 Coprinus is a generic difference of some importance. 



In their field characters the Bolbitii do bear a general resemblance 

 to the Coprini. Among these characters may be mentioned : 



(1) Thin flesh and relatively large gills. 



(2) Relatively long, slender, hollow stipes. 



(3) Delicacy and ephemeral nature of the fruit-bodies. 



(4) Deliquescence of the gills and pileus-fiesh. 



(5) Fruit-bodies often coprophilous. 



However, if instead of merely considering the more obvious 

 characters we study the whole organisation of the fruit-bodies, taking 

 into account both microscopic and macroscopic characters, then I 

 think we must conclude that the two genera stand far apart. Their 

 fruit-body mechanisms for the production and liberation of spores 

 are essentially different, and one could not be converted into the 

 other without important structural and physiological changes. 



